Abstract
Aim
To assess the role of Tc-99m labelled anti granulocyte monoclonal antibody Fab' fragment (Sulesomab) in the diagnosis of bone and joint infections.
Methods
We analysed the results of 95 patients referred with a clinical suspicion of bone and joint infections. There were 47 male and 48 female patients with a mean age of 60 years (range=16 to 89). Referrals were made for suspected infection of prosthetic total joint replacements (38), long bones (32), primary joints (12) and feet (13). Sulesomab imaging was done with 650 MBq of 99mTcSulesomab. The final diagnosis was determined by conclusive microbiology, culture and/or histology, intra-operative findings, aspiration, complementary investigations like CT/MRI and long term clinical follow-up. The findings of 99mTcSulesomab images were compared with the clinical outcome to arrive at the decision of True Positive/ False positive/ True negative/ False negative results. Using the above definitions sensitivity, specificity and diagnostic accuracy of 99mTcSulesomab for suspected bone and joint infection were calculated.
Results
58/95 patients had normal or equivocal blood results. Plain radiographs revealed no abnormality or were inconclusive of infection in more than half of the patients. Outcome classification revealed 29 true positives, 56 true negatives, 9 false positives and one false negative. The overall sensitivity was 96.66% and specificity 86.15% with a negative predictive value of 98.24%. The individual sensitivity and specificity of each category was compared. Diagnostic accuracy for long bone infections (96.87%) was the highest than any other group.
Conclusion
99mTc Sulesomab imaging has a high sensitivity and specificity in a heterogeneous group of orthopaedic bone and joint infections. With a high negative predictive value, this test seems to be useful in excluding orthopaedic infection rather than confirming it.
